A substance found in star athlete Oscar Pistorius's home during a search by police investigating the killing of his girlfriend is a herbal sexual stimulant, a South African newspaper reported Sunday.

The prosecution said during Pistorius's bail hearing last week that police had found two boxes of "testosterone" and needles in his Pretoria home, but the defence countered that it was a legal herbal remedy known as testocompasutium coenzyme.

The City Press newspaper said Sunday the remedy was a combination of vitamins, herbal cures partly derived from animal organs.

Sexual energy

Sports physician Jon Patricios told the paper the product is used to boost sexual energy, but that athletes are not advised to use it since it may increase their testosterone levels.

"This is not an anabolic steroid and it is unlikely it will lead to irrational anger," he said.

The National Prosecuting Authority has said it was awaiting the results of forensic tests to determine what the product is.

Pistorius, 26, an Olympic and Paralymic hero, was freed on bail on Friday ahead of a trial on a murder charge over the Valentine's Day killing of his girlfriend Reeva Steenkamp.

The International Paralympic Committee said the double amputee was tested twice during the London Paralympics in 2012 and tested negative.